Thanks.... seriously... it's easy to find many saying how horrible an engine this is yet, it sure looks to have a thoroughbred sleeping inside.
I don't know the things to be done in order to keep one together at higher power outputs and just like to know if the info is available.
I did study the twin turbo version and it sure appears there is a relatively easy way to pump enough oil through it to take car of most anything other than two rockers sharing the same lobe.
I'll get in touch with some of the people who are building and breaking a few.
Heck, it's been in production for 40-ish years!
Originally Posted by Rich W
I am not sure you are going to get the answers for "boost until failure" questions for the PRV V6 on this forum.
In fact, I am not sure if you have answers for "forced fed" versions of Pontiacs, Ducatis, Scotts, Nortons, etc.
For more details in taking the PRV V6 to the limit and beyond, both stock and boosted, you may want to check
the "older" Volvo forums, especially for work done by John Lane in the Pacific Northwest (Seattle, WA area).
John runs a Rally Car version of a Volvo 262 SPE with probably the most powerful PRV V6 in the US.
In the past, the car was running 515 ft/lbs at the rear wheels on the dyno while running 11 psi boost.
The car is currently running 18 psi boost and it is known to implode K&N cone filters on a regular basis.
If you want to go WAY OUT THERE, check the back issues of Race Engine Technology (not sure the issue).
There is an article about how to get in excess of 900 BHP out of both a 2.8L and a 3.0L PRV V6 engine.
Nobody is saying it's a horrible engine. It is great for what it was designed for. Any well engineered motor is a system and it is ALL made to a certain level of power and cost. There is no "magic bullet" thing you can do to improve it. To get more out of the PRV you have to do it all. Just putting in forged pistons won't do it. Just adding cams won't do it. Just working on the valve train, just adding a turbo or super charger, etc. To go to higher power levels you have to do something to ALL of the systems. This also includes the transmission. You are right, you can get more power out of it but there is limited experience with it in the US. This motor was much more popular in Europe so the answers you seek (and the parts you will need) are over there. In the US it is just easier to swap the motor out for something with parts that are more available here and more experience here. If your intention is to make a Delorean a screamer, an engine swap is the way to go but your choice of transmissions is very limited. The most obvious one is the Porsche. They are hard to get and expensive. Look at what others have done first. It is a LOT cheaper than trying to reinvent the wheel yourself. There have been some very nice conversions and some "not so nice" ones. There are not a lot of PRV's that have been raised to very high power levels. Most stop at forged pistons and some boost. After that the transmission is not going to live long and if you are going to change the transmission you might as well change the motor too.
David Teitelbaum
Ive heard alot of people saying the PRV is a horrible engine, they are wildly misinformed.
Well, they did do some things which could be better. The cam chains are kinda puny and the one variation with the two rockers sharing a lobe didn't seem to work out well.
I'm going to snag some slightly shorter Carillos or Pankls and Silvolites with correspondingly correct compression heights. I suspect a camshaft ground with modern cam dynamics, from good material, properly treated, will follow soon. It looks like some 26-32 degree tulips would be nice as well.
Do you know if anyone has HiVo'd one of these? I think I saw one factory variant, forgot which one, that came fitted with HiVo cam chains. I can't wait to get a spare engine to scatter it's parts and see how much room there is for things like that.
However, I do agree that many people despise and malign this engine, regardless if Volvo people, Eagle or Dodge factions. It's much easier for me to run into people who don't like it, than adoring fans.
I own a prepped Delorean and also an Alpine, and prepared some PRV engines.
Changed 3 engines in my delorean. Also remember that odd-firing prv are quite different even in little things from the late even-firing, even if seems similar. For example different ( bigger ) oil pump, different rocker arms, different liner base diameter, rods etc etc... So the blocks seems similar and match some mouting holes, but different animals.
In an aspired preparation PRV the biggest numbers i know are 293hp for N/A 2.8 from Renault when they run the car in the 80s rally, and one who did 307hp from a PRV 3.0lt N/A last year, with modern technology and EFI.
For getting this numbers you need compression around 11,5:1, 300+ degree cams, direct throttle intakes, some lightining and RPMs. After around 8200rpm stock valve springs start to bunce, and can hit the pistons. For gettin 9000rpm safely you need with the high numbers cams also reinforced springs.
On an evenfiring N/A than the oil supply is adeguate: there are lot of difference in rocker arms, lubricating passages on the axis of arms etc, and an oil bath for cams in the head castings.
Early Odd-firing lacks lot of this things: so could be better.
This are pistons i have now on the shelf for an evenfiring N/A PRV prep, CR aroun 11:1.
comparison with stock.
In Turbo preparation, Peugeot at Lemans run also around 900hp from PRV. Not so reliable tought, and was quite different head castings etc.
But for a normal turbo PRV, the biggest problem I found is the oil supply start to get weak: tollerances are not so good in the old PRV, better in the newer ones, so when getting hot, the oil supply start to loose pressure, if you have a very hot engine, and an addictional oil use, like a turbocharger. That's why i found so important that late evenfiring has a better, bigger, oil pump, and i went with a twinturbo in my delorean using a late evenfiring PRV. Late prv also has cross side bolt for reinforcing. Quite indistructible, apart the oil problem. I just saw one time a cracked liner, and bent rods, on a Renault Safrane buturbo, but was caused by a poor lubrication.
So, just take car of it: good oil cooler and good oil.
The PRV oil pump surfaces are integrated in the block, so if get damaged, you can't do anything but change the entire block.
The 24v version, the first one, had a rocker arms problem with get ruined for poor lubrication, and the parts ruined the oil pump. Late one has ceramic follwers, so is more good.
But still idraulic followers, wich is not good for rpm, and you can max put in a 260deg cams.
I prefer the 12v version, much more easy to find, work, find and make performance parts and reliable.
Andrea - #01748 3.0lt Twin Turbo EFI, custom brakes, suspensions, manual trans - black interior -
PRV's lover. Club Italiano Delorean www.dmc12.it
I stumbled across Guy Croft's forum and was reading the PRV thread there just a few minutes ago. I'm a bit confused as to the stock piston and what appears to be non-existent squish. Does the stock piston actually positive or zero deck or is it what I think it is, a reverse dished piston with actual negative deck? You may be interested in reviewing that thread as the carbon formation and other various chamber patterns are quite peculiar.
I think I'll sign up and chime in on this thread. I think the chambers and crowns should be dead smooth with that inexplicable half moon gouge filled in. It also appears to need flattops so as to have at least some squish. I do think the injector is indeed too close to the valve head although GC doesn't seem to think so. Maybe if the intake seat was 45 degrees the affect wouldn't be so pronounced. I don't know the valve material, but, probably not too much of a concern on that turbo engine if using Nimonic 80A.
How much larger is the stock piston bore than the diameter of the chamber or are they the same size with respect to the cylinder wall?
All I want to do with the stock engine is optimize what is there first without turning a bolt or nut to access the engine's internals. I'm gathering pieces to do headers with skinny long primaries and already have some nice tight collectors. My CIS is FUBAR at this point so I'm going to use 2 racks of 3's and see how cold the pulse tuned runners will get.
If that goes well, maybe slip in some flattops, port the heads and detail the chambers while the heads are off.
BTW... nice pistons and they look intelligent. I notice GC does not seem to polish his chambers and crowns dead smooth. I certainly do and always have since nobody has ever given me any reason to support chamber/crown roughness or sharp edges. It appears from the pix that your pistons do not have any sharp edges, which is nice as most Hi-Po pistons are merely kits as far as I'm concerned. Will you polish the crowns dead smooth?
Most of my experience is with hemi's, semi-hemi's and wedge's, although I've built many others including some very fast side valves. NA, blown and NOS. The other guy in my shop is a pent roof wizard. I do like the prv chamber and it does appear to have much promise.
Also, why does the DMC engine have different cam timing from one bank to the other? I know most of the other versions do not. Are the ports, head or intake runners, actually different from one bank to the other as has been suggested to me?
I also haven't found a spec on the rocker arm ratio's and they appear nearly 2:1 and almost with room for rollers, especially if bumping down the ratio just a tiny bit. Do you know the ratio? Rollers on both ends and a shoe box looking lobe would be teats.
Have you ever seen a header for the odd fire prv with multiple crossovers, with long skinny primaries and a tight long collector? I'd be interested in buying a set already made even if I had to cut and section them to fit the DMC. Even without crossovers or suitable collectors, it would still save me some time.
I've plenty of other things I need to be doing.
Thanks again for the informative sharing.
I'll load up some pix of a bit of my handiwork in the near future.
Originally Posted by cineman
I own a prepped Delorean and also an Alpine, and prepared some PRV engines.
Changed 3 engines in my delorean. Also remember that odd-firing prv are quite different even in little things from the late even-firing, even if seems similar. {snip}
But still idraulic followers, wich is not good for rpm, and you can max put in a 260deg cams.
I prefer the 12v version, much more easy to find, work, find and make performance parts and reliable.
Last edited by EarlHickey; 05-07-2012 at 12:36 AM.
Originally Posted by Rich W
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love the look of those domed pistons!
